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To those who own 2ohm amps.
- Thread starter allexcosta
- Start date
I run my Mesa BB750 into a 2-ohm load (pair of Aggie GS212's @ 4ohms) for larger gigs, and have never had a problem.
The fans definitely do get to working harder.
I did a test run in my garage when I first got the setup, turned it way up on the volume.
It was grin-inducing - watching the lights go dim in sync to my playing!!
The fans definitely do get to working harder.
I did a test run in my garage when I first got the setup, turned it way up on the volume.
It was grin-inducing - watching the lights go dim in sync to my playing!!
My M/B M-2000 owners manual says:
2000 watts @ 2 ohms
recommended load 4 ohms
I don't know exactly what M/B means by using the word "recommended". Maybe they're covering their butts in case someone runs it @ 2 ohms for 6 hours at full power at an outdoor gig in direct sunlight when it's 102 F out and they melt their amp. They can then say, "We told you that wasn't recommended."
But I run mine at 8 ohms because that's what my cabinet is and since my band plays at a very low stage volume, I've never needed to even push it even at that impedence.
2000 watts @ 2 ohms
recommended load 4 ohms
I don't know exactly what M/B means by using the word "recommended". Maybe they're covering their butts in case someone runs it @ 2 ohms for 6 hours at full power at an outdoor gig in direct sunlight when it's 102 F out and they melt their amp. They can then say, "We told you that wasn't recommended."
But I run mine at 8 ohms because that's what my cabinet is and since my band plays at a very low stage volume, I've never needed to even push it even at that impedence.
+1. I think a few of us are showing our age hereI........These days, with modern SS amps from reputable manufacturers, it's pretty safe to assume that if the amp's spec says it can work safely into a given minimum load, it can. However, allexcosta's worry is understandable. We all remember a time not so long ago when this was not the case: a few well-known SS amps that claimed to be able to run into 2 Ohms could actually only do so...er..."in theory".
I also remember the first lot of 2 ohm amps being a little unreliable. But that was a good 15 years ago or more. Indeed nowadays, 2 ohms is the new 4 ohms in that most amps seems to use 2 ohm as the standard minimum impedance spec.
My Traynor YBA200 actually has less wattage at 2 ohms. only 180 watts (i think), but imagine 2 8x10 cabinets cranked with an all tube amp. Anybody else notice that Traynor removed the 2 ohm bit in the YBA200-2 manuals? Basically saying it's only stable down to 4ohms.
The other nice thing about this amp is it is full wattage in either 4 or 8 ohms.
The other nice thing about this amp is it is full wattage in either 4 or 8 ohms.
This is true of all tube amps. The amp puts out the same power and the output transformer does the impedance matching. Basically, the amp always sees the same impedance.
Alvaro Martín Gómez A.;5299509 said:
Same here. It's a tank, and it sure sounds awesome, especially for a solid state head!
Power is power. 2 ohms or 4 ohms doesn't matter. MFG's don't make amps that go to 2 ohms so that you can get more power out of them. They could just as easily make the same amp put out the same power but do so at 4 ohms instead of 2 ohms. The 2 ohm thing is for expandability purposes more than anything else. You can hook up four 8 ohm cabs to a 2 ohm head, or two 4's. Basically, whatever cabinet selection you can run off a 4 ohm head, you can double it on a 2 ohm head.
Lots of people make their cabinet selections based off the head they want to use. If they choose a 4 ohm head, then they'll have to pick cabs that don't go below that. Others, such as myself, like to choose cabinets based on their own merits separately, and then have the option to combine them when needed. It's the modular approach to building a rig. For those like me, a 2 ohm capable head provides a whole lot of flexibility.
Also, the Genz design mentioned already in this thread is great. The GBE's are designed to maximize power output at both 4 and 2 ohms, so that the power differences are minimal. My 1200 puts out 1000 watts at 4 ohms, and 1200 watts at 2 ohms. Not a much of a difference at all in terms of power.
Lots of people make their cabinet selections based off the head they want to use. If they choose a 4 ohm head, then they'll have to pick cabs that don't go below that. Others, such as myself, like to choose cabinets based on their own merits separately, and then have the option to combine them when needed. It's the modular approach to building a rig. For those like me, a 2 ohm capable head provides a whole lot of flexibility.
Also, the Genz design mentioned already in this thread is great. The GBE's are designed to maximize power output at both 4 and 2 ohms, so that the power differences are minimal. My 1200 puts out 1000 watts at 4 ohms, and 1200 watts at 2 ohms. Not a much of a difference at all in terms of power.
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Says the amp will put out 225 watts per channel at 8 ohms, 350 watts per channel at 4 ohms, and 500 watter per channel at 2 ohms.
In addition it will put out 700 watts bridged mono at 8 ohms and 1000 watts bridged mono at 4 ohms.
Are you going to be running both sides at 2 ohms? If you're not I would say put a 4 ohm load on each side of the power amp... each cab will see 350 watts opposed to 250 watts each that you would get at 2 ohms There won't be much volume increase but you'll have more clean headroom. Do this only if you're going to be using one side at 2 ohms,if you'll actually be hooking up two 4 ohm cabs or four 8 ohm cabs per side then disregaurd any of that.
Peace
-Benny
Scroll down to page 6
Says the amp will put out 225 watts per channel at 8 ohms, 350 watts per channel at 4 ohms, and 500 watter per channel at 2 ohms.
In addition it will put out 700 watts bridged mono at 8 ohms and 1000 watts bridged mono at 4 ohms.
Are you going to be running both sides at 2 ohms? If you're not I would say put a 4 ohm load on each side of the power amp... each cab will see 350 watts opposed to 250 watts each that you would get at 2 ohms There won't be much volume increase but you'll have more clean headroom. Do this only if you're going to be using one side at 2 ohms,if you'll actually be hooking up two 4 ohm cabs or four 8 ohm cabs per side then disregaurd any of that.
Peace
-Benny
Peavey Max 700 - run many, many times at two ohms, for four hours non-stop. No problems.
SWR - for seven years, run at 2.67 ohms nearly every time I turn it own. Has never overheated, never shut down, no problems whatsoever.
SWR - for seven years, run at 2.67 ohms nearly every time I turn it own. Has never overheated, never shut down, no problems whatsoever.
I ONLY run my amp at 2 ohms. A 210XLT on top of a 212XLT. Both 4 ohms.
I had an outdoor gig. Hot as hell in the dead middle of July. 90 degrees in the shade at 11am. My whole rig was sitting in the sun for 1-1/2 hours before I even started setting up. My rack is an SKB US Roto rack and is jet black and airtight. When I opened the lids it was like taking cookies from an oven. Scary hot inside. Set up, played the gig, ROCKED, not a single glitch.
I will never question my amp's build quality, no matter what the horror stories may predict.
If your amp is rated to drop down to 2 ohms, you have absolutely nothing to worry about.
My Genz Benz head does NOT run hotter at 2 ohms. Like Bryan, I've run this head outside in sweltering Gulf Coast heat with no problems. It is the best made, coolest running head I've ever owned.
My wt550 that I used to have was run at 2 ohms a good bit. It definitely didn't run nearly as cool as the GBE 1200, but it never went thermal either. The fan was quite noisey, but like Bryan I had no problems with it at 2 ohms.
Designing an amp to run optimally at 2 ohms is no mystery. There's no magic to it. The problem is that so many MFG's make amps that should really only run at 4 ohms, then rig the amps to limp along at 2 ohms with VI limiting and other things. The result is non-optimal performance, and they'll run hotter, perhaps even shut off.
Ohh btw, I forgot to ask this... Does your 2000RB have the dual fans? There were some problems with over heating with the ones that only had one fan. Might be worth looking into if you plan on running it 2 ohms, or in bridged mode.
Peace
-Benny
Peace
-Benny
